Liability Related to Sale of Future Royalties -Schedule of Activity Within Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Liability Related To Sale Of Future Royalties [Line Items]
Current portion of liability related to sale of future royalties	$ (48,601)	$ (37,889)
Liability related to sale of future royalties, non-current	89,005	133,460
Royalty Agreements
Liability Related To Sale Of Future Royalties [Line Items]
Beginning balance	171,349	193,298
Zolgensma royalties paid to HCR	(56,219)	(48,226)
Interest expense recognized	22,476	26,277
Ending balance	137,606	$ 171,349
Current portion of liability related to sale of future royalties	(48,601)
Liability related to sale of future royalties, non-current	$ 89,005